66 Chase et al: Gloomy Scale Management Table 1. Insecticide products used in efficacy trial against gloomy scale in Rock Hill, South Carolina, USA in 2019. Product Manufacturer Distance* Horticultural oil* Transtect Altus Valent Corporation, Walnut Creek, CA, USA Lesco Inc., Cleveland, OH, USA Rainbow Treecare Scientific Advancements, Minnetonka, MN, USA Bayer, Leverkusen, Germany *These products were mixed together for this trial. Products, Rates, and Experimental Design We selected products (Table 1) based on their historic use (pyriproxyfen, dinotefuran) and potential to be included into a GS management program (flupyradi- furone). Each GS tree was assigned randomly to 1 of 6 treatments using a Microsoft Excel spreadsheet: untreated controls, dinotefuran applied during crawler activity (29 May), pyriproxyfen plus horticultural oil applied in the spring during crawler activity (23 May), flupyradifurone applied in the spring during crawler activity (T1 ; 23 May), flupyradifurone applied in mid-summer (T2; 2 July), and flupyradifurone applied in late summer (T3; 30 August). All treatments were conducted in the year 2019. Tree diameter at breast height (DBH) ranged from 7.3 cm (2.9 in) to 19.1 cm (7.5 in). All products were applied according to the label (Table 1). We applied 59.14 mL/2.54 cm (2 oz/1 in) DBH of dinotefuran as a basal bark spray with a back- pack sprayer (15.14L Chapin Commercial Backpack Sprayer [Model 61900], Batavia, NY) at 96.53 kPa (14 psi) CFV and an 8006 TeeJet® fan nozzle (Spring- field, IL). A surfactant (Scrimmage, Exacto Inc., Sharon, WI) was added to dinotefuran at a rate of 88.7 mL/3.78 L (3 oz/1 gal) water. We applied the dinotefuran and surfactant mix until the bark was wet from a height of approximately 1.37 m (4.5 ft) to the ground. In this study, we combined pyriproxyfen with hor- ticultural oil (see Table 1). Combining pyriproxyfen with horticultural oil is a standard practice, and recent research (Quesada et al. 2018) has shown that oil is superior to soaps at suppressing armored scales. All ©2021 International Society of Arboriculture foliar flupyradifurone and pyriproxyfen plus horticul- tural oil applications (Table 1) were conducted with a Green Garde JD9-C spray gun (H.D. Hudson Manu- facturing Co., Lowell, MI) from a rig specifically designed for plant health care operations at a pressure between approximately 1034 to 1378 kPa (150 to 200 psi). Lesco Spreader-Sticker (Lesco Inc., Cleve- land, OH) was added to all flupyradifurone applica- tions at a rate of 1.77 mL/3.78 L (0.06 oz/1 gal) water. Control trees had no treatment applied. All treatments had 9 replicates. Evaluation and Statistical Comparisons Six branches (technical replicates) were harvested from each tree (biological replicate) on 28 October 2019 using pole clippers and hand pruners, trimmed to 15 cm in length, placed in plastic bags, and immediately trans- ported to the Bartlett Tree Research Laboratories where they were stored at 4 °C until scale densities could be counted. The branches selected for density counts were of similar diameter and among the most heavily infested with GS on the trees. Once at the laboratory, GS-infested branches were cut into lengths of 152 mm and then individually inspected using a standard dis- secting scope. We counted live GS and obtained a ratio of the number of live GS per mm length of branch. High levels of GS survival (≥ 75%) were observed on trees in some of our treatments (e.g., untreated con- trol trees). In these instances with high survival, branches were trimmed from 152 mm to a minimum of 30 mm, and survival was counted on this trimmed section of stem to obtain the ratio. This was done in order to decrease the time it took to perform counts Flupyradifurone 17.09 310.52 mL (10.5 oz) Foliar 23 May (T1 2 July (T2 ), ), 30 August (T3 ) Active ingredient (AI) % AI Pyriproxyfen Refined petroleum distillate Dinotefuran 11.23 98.8 70 Rate used (per 378.54 L [100 gal]) 236.59 mL (8 oz) 1892.71 mL (0.5 gal) Application method Foliar Foliar 10,646.5 mL (360 oz) Basal bark spray Date(s) of treatment 23 May 23 May 29 May
March 2021
| Title Name |
Pages |
Delete |
Url |
| Empty |
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success. You will be contacted by Washington Gas with follow-up information regarding your request.
This process might take longer please wait
